Antioxidant status of thyme and rosemary leaf powders and their effect on lipid oxidation of minced meat during cold storage

Abstract

This study examined the antioxidant capacities of rosemary and thyme leaf powders and their impact on lipid oxidation in minced beef during refrigerated storage. Five types of minced beef were prepared: Control (meat without additives), TLP 0.2 (meat + 0.2% thyme leaf powder), TLP 0.4 (meat + 0.4% thyme leaf powder), RLP 0.2 (meat + 0.2% rosemary leaf powder) and RLP 0.4 (Meat + 0.4% rosemary leaf powder), and stored at 4oC for seven days. Results revealed that RLP exhibited higher (P < 0.05) phenol (398.75 mg GAE/g), flavonoid (172.30 mg QE/g) and vitamin C (82.05 mg/g) contents than TLP (297.61 mgGAE/g, 65.72 mgQE/g and 52.56 mg/g, respectively). Extracts of RLP demonstrated higher (P < 0.05) antiradical activity than TLP. During day zero of storage, there was no significant effect of leaf powders on the minced beef. However, on day three, both RLP and TLP at 0.2% and 0.4% significantly reduced lipid oxidation in the minced beef than the control group. Also on day seven, the lipid oxidation of RLP and TLP minced beef was greatly reduced (P > 0.05) compared to the control group. Thus, application of RLP and TLP could serve as effective preservatives, inhibiting lipid oxidation in meat products.